This invention relates a seal assembly for a wafer grinding machine.
As is known, various types of machines have been provided for the grinding of an edge of a wafer such as a silicon wafer, for example, into a parabolic profile. For example, U.S. Pat. No. 4,638,601 describes an automatic edge grinder having a grinding station in which a wafer is held and rotated while a grinding wheel grinds the edge of the wafer into a desired shape.
As is known, during the grinding of the edge of a wafer, debris from the wafer edge as well as from the grinding wheel is formed. Further, it is also known that this debris must be prevented from depositing onto the planar surfaces of the wafer as such could destroy the usability of the wafer in forming semi-conductor chips. Accordingly, various techniques have been employed to remove any such debris from the grinding environment of a grinding machine or to otherwise preclude depositing of the debris onto the surfaces of the wafer. For example, as described in U.S. Pat. No. 4,638,601, the wafer to be ground has been held between a head and a chuck via annular lip seals while compressed air has been blown through the head as well as the chuck in order to deliver a flow of air for blowing ground particles from the surfaces of the wafer outwardly of the annular lip seals. In addition, the head and chuck have been disposed within a housing which can be closed and evacuated during a grinding operation to draw off ground particles.